1. Field of the Invention
The present invention relates to an optical information reader and an optical information reading method. For example, the present invention is used for a tabletop type or hand-held type bar code reader comprising a switch to which any of a plurality of functions can be assigned.
2. Description of the Related Art
Nowadays, a bar code is used in application of identify a commodity code, etc. The bar code comprises contiguous lines different in width so that it can represent alphanumerics by bar and blank portions. The bar code, for example, represents a universal product code. To read such a bar code, a bar code scanning device is used as an optical information reader. The bar code scanning device generally is called a bar code reader, a bar code scanner, etc.
The bar code scanning device generally comprises a configuration as shown in FIG. 6. The bar code scanning device shown in FIG. 6 comprises a bar code read section 1 and a signal processing circuit 2. The bar code scanning device scans a bar code label 3 with a bar code printed through the bar code read section 1, detects reflected light, and reads information of the bar code by the signal processing circuit 2.
In FIG. 6, a laser projection circuit 4 projects light such as laser light to a galvanometer mirror 5 and reflected light on the galvanometer mirror 5 is scanned over the bar code. The bar and blank (monochrome) portions making up the bar code differ in reflectivity. The blank portion provides a large reflected light amount. The bar portion provides a small reflected light amount. The reflected lights are gathered on a light gathering mirror 6 through the galvanometer mirror 5. The gathered reflected lights are taken out as an analog signal in time series through a band-pass filter 7 and a photodiode serving as a light reception element 8. The analog signal is sent to the signal processing circuit 2.
The signal processing circuit 2 has a light reception circuit 9, an AC coupling circuit 14, an amplification circuit 10, a filter circuit 11, a binarization circuit 12, and a decode circuit 13. The light reception circuit 9 receives a signal from the bar code read section 1. The AC coupling circuit 14 allows the AC component of output of the light reception circuit 9 to pass through. The amplification circuit 10 amplifies the output signal of the AC component provided by the AC coupling circuit 14. The filter circuit 11 filters the amplified signal. The binarization circuit 12 binaries the filtered signal. The decode circuit 13 decodes the information recorded on the bar code. The decode circuit 13 generally is implemented as a CPU, etc. The digital signal binarized by the binarization circuit 12 is sent to the CPU, which then decodes the signal by a program according to an algorism.
The bar code readers generally can be classified into fixed-type, handy terminal type, and tabletop type according to the shape of the bar code reader.
[Fixed-type Bar Code Reader]
The fixed-type bar code reader is used with a factory production line, in a machine, etc. It is disposed on a side of a conveyor, a wall, or the like for use so that the read area of the bar code reader is aimed at a bar code put on a transported object on the production line. The bar code reader portion of this type has a function of decoding bar code information and transmitting the decoded data to a host computer. In other words, processing for the decoded data generally is performed in the host computer and the bar code reader portion does not have such a function.
[Handy Terminal Type Bar Code Reader]
The handy terminal type bar code reader is used for commodity management, inspection, etc., in a warehouse. It is assumed that the user carries the handy terminal type bar code reader and uses it in the field. Thus, the handy terminal type is convenient for carrying and further the terminal itself comprises a processing function of a commodity management program, etc., responsive to the use purpose. That is, unlike the fixed-type bar code reader, the handy terminal type bar code reader completes operation solely.
[Tabletop Type Bar Code Reader]
The tabletop type bar code reader is used for POS management, etc., at a checkout counter of a convenience store. The bar code reader of this type transmits the data to a host computer. Since the bar code reader is shaped like a gun, it is sometimes called a gun-type bar code reader. Like the handy terminal type bar code reader, the tabletop type bar code reader also has a compact shape easily handled by the user. The handy terminal type and tabletop type bar code readers differ in that the handy terminal type bar code reader completes operation solely; whereas the tabletop type bar code reader operates in conjunction with the host computer. The read portion of the tabletop type bar code reader generally has only a function of decoding a bar code. That is, it can also be grasped as a handy terminal type bar code reader comprising the read portion of the fixed-type bar code reader.
The appearance of the tabletop type bar code reader is, for example, as shown in FIGS. 7A–C. The tabletop type bar code reader is provided with a trigger switch 17. Generally, a laser is projected while the trigger switch 17 is turned on. The user projects a laser to the target bar code label by operating the trigger switch 17 and reflected light is read into the bar code reader. In addition to the trigger switch, the tabletop type bar code reader is sometimes provided with a switch to which a specific function is assigned.
However, the tabletop type bar code reader in the related art has a switch to which a specific function is previously assigned, and the user cannot assign any desired function to the switch. For example, the tabletop type bar code reader shown in FIGS. 7A–C is provided with switches in addition to the trigger switch 17, but predetermined functions are previously fixed to the switches and cannot be changed to any desired function by the user.
On the other hand, in recent years, because of an increase in demand for bar codes, making a bar code reader multi-function has also been required. In response to this, various functions are added to the bar code reader, but the operation of each function becomes complicated and usability is impaired. If the user needs to execute a plurality of steps to call a function, he or she interrupts the work and needs to check the procedure on the manual or keep the procedure in mind; this is a cumbersome task. To facilitate calling a function, a plurality of switches can be provided in a one-to-one correspondence with the functions; however, in doing so, the number of the switches is increased, resulting in a rise in manufacturing costs. Further, as the number of the switches is increased, the user confuses the switches and may operate the switches erroneously, the operability being worsened. If the bar code reader is made multifunctional, only some of the functions which are required for each user can be assigned to the switches; however, the frequently used functions or the functions to be easily called are limited.
Essentially, the required functions vary depending on the use state of the bar code reader and the use mode of the user. The manufacturer of the bar code reader previously assigns the seemingly frequently used functions to switches, but it is impossible to estimate diverse use modes and completely cover the use modes. If it is made possible for the user to specify and change function assignments to the switches as desired, an ease-of-use environment as setting responsive to the use mode can be provided for the user.